“The noisy neighbours are getting louder” read the banner in the Colin Bell stand at the Etihad Stadium - and that deafening roar at the full-time whistle confirmed Sir Alex Ferguson’s worst fears.

Manchester is blue tonight. So is Vincent Kompany, the City captain who put the club in line for a first title since 1968 with a bullet header in the 46th minute to decide the game and, probably, the destination of the Premier League trophy.

The biggest derby ever? The most important domestic game in Premier League history? It was ugly, tight and scrappy, but it was a result City deserved. It was nothing like ‘the 6-1’ - as it’s known on this side of town - but it was more important. It leaves Roberto Mancini’s side knowing they will be champions if they win their final two fixtures, away at Newcastle and at home to QPR.

United, level on points but with a vastly inferior goal difference, will be there if their rivals slip up. But the momentum is with City, the players knew it as they celebrated on the full-time whistle, joining together for a group huddle in the centre circle.

GOAL!! Kompany scores in the first minute of stoppage time with a poweful header five yards out! He shrugged off Chris Smalling who was marking him and sent the hosts into the lead with barely any time left on the clock.

The City captain led by example with excellent movement and a thumping header to leave the club in line for a first title in 44 years. Very strong defensively.

The nature of City supporters means they will lean towards pessimism, fear dropped points when they travel to an in-form Newcastle team who thumped United at St James’ Park earlier in the season. Mancini struck the same note of caution in his post-match interview, quite rightly suggesting that City’s game at Newcastle will be the true title decider, not tonight.

But with players like Kompany in the team, it feels like City have truly stepped out of United’s shadow. The Belgian was magnificent throughout, commanding at the back and not giving Wayne Rooney even a glimpse at Joe Hart’s goal in the entire 90 minutes.

At the other end, he showed the drive and desire that makes the difference in games of so few chances. After losing Chris Smalling with some clever movement, he had the willpower to get on the end of David Silva’s corner and thump his header past David de Gea in the United goal.

What a bizarre campaign it has been for Kompany against United. Having made a mistake in the Community Shield that cost City the match, he was sent-off for a two-footed challenge in the FA Cup defeat to Ferguson’s side in January. Now he is being hailed for a title-deciding goal.

Never has this stadium witnessed such an atmosphere in its 10-year history. When it opened in for the Commonwealth games in 2002, City had just been promoted from the First Division having been in the third tier a few years earlier. A night like this was beyond their wildest dreams.

After the final whistle, after the players had made their way back to the changing rooms, the Etihad Stadium still rocked to the sound of Blue Moon and then Wonderwall. Liam Gallagher led the chorus from his private box, the City players could be heard celebrating from the other end of the tunnel.

The fact is that City have done the double over United in the league this season and deservedly so, being by far the better side in both fixtures. They have also topped the division for 29 games this season. Few could argue they don’t deserve to win the title.

Players like Kompany certainly deserve to win the title. And the City fans, those noisy neighbours, are singing at the top of their voices.